This invention relates to a wind turbine of the type having a rotor with a relatively large number of vanes. Such wind turbines, which are known by the name of American wind turbine or polder draining mill, are known per se, and are used for various purposes, such as pumping water or generating electricity, and the like.
A great advantage of this type of wind turbine is that useful energy is already provided at a low wind force. Another advantage is that such a wind turbine operates with a low speed of the wheel or rotor, so that, under normal conditions, the mechanical load is relatively low, and the vane may be simple and hence inexpensive.
A disadvantage of the American wind turbine is that, owing to the large number of vanes, it has a large wind catching area, and consequently has a poor resistance to high winds, and to gale force winds. Indeed, the known multi-vane wind turbines should be provided with a transverse wind vane, which at a pre-determined wind force automatically turns the rotor out of the wind. In this way, the wind turbine can be prevented from being damaged at high winds, it is true, but at the same time it will cease to provide energy.